The invention relates to a continuous, fully integrated system and method for producing nonwoven webs consisting of bleached cotton fibers.
Bleached cotton fibers have been used in many nonwoven fabric applications for cleanliness and absorbency such as wipes, premoistened towelettes, absorbent pads, etc. The purified, absorbent fibers are particularly advantageous in hospital and medical applications such as disposable sheets, blankets, gowns, and bandages, and, particularly, because of their biodegradability. Typically the bleached cotton fibers are made into a nonwoven web and then fabricated for the particular end use.
The typical process has included many separated processing steps. Typically, raw cotton fibers are bleached at a remote bleachery using a large vat. The bleached fibers are dried and pressed into bales. The bales of bleached cotton fibers are then transported to a textile mill at another location where they are processed further by a nonwoven carding system into nonwoven webs in a conventional manner. Bleaching processes have not been a part of nonwoven textile processing lines. As a result, the textile process has been fairly inefficient incurring transportation costs, and inefficiency through piecemeal processing.
Various textile process lines for woven and nonwoven fabrics are known and have been proposed in the past. Various processes and systems are known for opening, cleaning, and blending fibers, for example, U.S. Pat. No. 2,718,671. Various processes and systems for opening fiber bales, and opening and cleaning the fiber before being carded into a web for woven or nonwoven applications are known, for example, as shown in U.S. Pat. No. 4,535,511.
It is known to make webs formed from synthetic fibers more integral by hydroentanglement techniques. Various hydroentanglement techniques and apparatus for producing integral webs having various patterns are shown in U.S. Pat. Nos. 3,494,821; 3,486,168; 3,485,706; 3,508,308; and 3,493,462.
Because of the increased demand for the bleached cotton fiber, for both woven and nonwoven products, it has become necessary to use lower grades of cotton. This has rendered the prior bleaching and textile processes unsatisfactory because they do not satisfactorily process the lower grade of cotton. Accordingly, an important object of the present invention is to provide a system and method for producing bleached cotton, nonwoven webs in a single processing line under one roof.
Another object of the invention is to provide a continuous fiber preparation process capable of converting low grade, dirty, short stable cotton fibers into a clean blended fiber web.
Another important object of the invention is to provide an efficient textile process system and method which begins with the opening of raw cotton fibers from bales and ends with the production of nonwoven webs ready to enter a cotton bleaching process in a continuous system.
Another object of the invention is to provide a continuous cleaning cotton system which dries the cotton fibers prior to cleaning so as to more efficiently and effectively remove trash and dirt particles.
Another object of the invention is to provide a continuous cotton cleaning system capable of adapting between extremely dirty cotton and mildly dirty cotton.
Another object of the invention is to provide a textile processing system and method wherein low grade raw cotton fibers may be processed and bleached and the bleached fibers may be subjected to further processing and production of a nonwoven web and prepared for further textile processing.
Another object of the invention is to provide a cotton processing system capable of producing cleaned and bleached cotton at an extremely high yield.
Another object of the invention is to provide a cotton processing system which reduces the cost per pound of processing clean and bleached cotton.
Another object of the invention is to produce surgical grade cleaned and bleached cotton at a rate of at least three to four thousand pounds per hour.
Another object of the invention is to provide a system which fully cleans and blends low grade cotton for the formation of cotton webs to be bleached.